Generally, a conventional screwdriver has a shaft and a handle which are firmly connected to each other and each of the shaft and the handle cannot be rotated individually. Thus, my previous invention disclosed in U.S. Pat. No. 9,108,304 provided a ratchet screwdriver which is configured to allow a shaft thereof to rotate individually relative to a handle of the ratchet screwdriver. Wherein the ratchet screwdriver comprises a handle, and a front end of the handle has a mounting member. A passage penetrates through the handle, and a chamber is formed inside a rear end of the handle. A shaft made of metal is inserted into the handle from the front end thereof, and a front end of the shaft has a function end while an insertion end is formed at a rear end of the shaft. A positioning recess formed on the shaft is configured to connect to the mounting member on the handle. A ratchet switch device located in the chamber of the handle has a base, and a room is formed inside the base. Moreover, two first slots are located at two opposite sidewalls of the base, and a recessed area formed at the rear end of the base has multiple notches formed at one side thereof. A through hole formed inside the recessed area is communicated with the room of the base, and a frame located in the room of the base comprises a recess located therein. A central hole penetrates through the frame, and a fastening member extends through the central hole. Each of two ends of the frame has a reception hole and a stop. Two engaging members are connected to two ends of the frame and each has ratchet teeth. Each of the two engaging members has an insertion which is inserted into the reception hole corresponding thereto, and the two engaging members contact the stops of the frame. A positioning member is located in the recess of the frame and the room of the base. The positioning member has a space located therein, and two second slots are located in two opposite walls thereof. A through hole penetrates through the positioning member, and a resilient plate is located inside the space of the positioning member. Each of two ends of the resilient plate has a contact end, and the two engaging members contact the contact ends respectively. Two positioning pieces and a ratchet member are respectively located in the room of the base, and the ratchet member further has ratchet teeth formed in outside thereof so as to be engaging with the ratchet teeth of the two engaging members. The first end of the ratchet member has a hexagonal reception recess into which the insertion end of the shaft is inserted. A tubular part extends from the second end of the ratchet member and extends through the through hole of the positioning member. The tubular part has an annular groove with which a clip is engaged so as to connect the ratchet member with the positioning member. A switch located in the recessed area of the base and connected with the frame has a boss extending therefrom which is engaged with one of the notches.
However, the conventional ratchet screwdriver is disadvantageous because: the ratchet switch device comprises excessive components so as to complicate the structure of the ratchet screwdriver and cause the difficulty in assembly further increasing the manufacturing cost. Moreover, the complicated structure also reduces the efficiency of momentum transfer and lowers the accuracy of operation. Therefore, there remains a need for a new and improved design for a ratchet screwdriver to overcome the problems presented above.